The Bill and Melinda Gates Foundation today became the latest backer to withdraw financial support for the American Legislative Exchange Council.

A foundation spokesman told Roll Call that it does not plan to make future grants to the conservative nonprofit, which has come under fire from progressive activists for its support of voter identification laws and other contentious measures.

The foundation, run by the co-founder of Microsoft Corp. and his wife, contributed more than $375,000 to ALEC in the past two years and was the target of an online petition launched today by the liberal Progressive Change Campaign Committee that garnered more than 23,000 signatures in a matter of hours.

&ldquo;We have made a single grant, narrowly and specifically focused on providing information to ALEC-affiliated state legislators on teacher effectiveness and school finance,&rdquo; said Chris Williams, the spokesman, noting that the foundation was never a dues-paying member. The foundation advocates for global health initiatives and efforts to reduce poverty.

It&rsquo;s the latest in a string of victories for groups bent on persuading corporations and foundations to cut ties with ALEC, which helps corporations advance their public-policy agenda in state legislatures.

Last week, Kraft Foods Inc., Coca-Cola Co. and Intuit Inc. each said they would withdraw support. The announcements came after months of behind-the-scenes pressure from another liberal group, Color of Change, an African-American advocacy group.

Color of Change went public today with demands that AT&amp;T Corp., one of ALEC&rsquo;s 21 corporate board members, also sever ties with the organization. Over the past year, the group has reached out to 15 consumer product companies that back ALEC, highlighting the organization&rsquo;s connections to voter ID laws passed in at least a half-dozen states.

Civil rights activists say the laws disproportionately target minority, student and elderly voters, who tend to vote Democratic, and could bar up to 5 million voters from the polls this fall. In recent weeks, other liberal groups have joined the effort.

Color of Change Executive Director Rashad Robinson said the group is using Internet appeals to pressure companies that have made explicit efforts to build a strong relationship with African-American customers.

&ldquo;Our goal is to ensure that these companies can&rsquo;t have it both ways,&rdquo; he said. &ldquo;AT&amp;T touts its support of civil rights groups and unions, which ALEC works to weaken.&rdquo;

A spokesman for AT&amp;T declined to comment.

Color of Change went live Wednesday with a website targeting Coca-Cola for its support of ALEC. Within hours, the company pulled its membership. Later in the week, Kraft Foods and Intuit, which develops Quicken and QuickBooks software, followed suit.

The public debate over Florida&rsquo;s &ldquo;Stand Your Ground&rdquo; law connected to the slaying of Trayvon Martin gave the advocacy groups more leverage over the companies. ALEC, they said, was behind an effort to pass similar laws in other states.

ALEC has played down its ties to both sets of laws. A spokesman declined to comment on the withdrawal of funders.

&ldquo;Our private members and legislators are independent thinkers and don&rsquo;t necessarily agree on all policy initiatives from ALEC,&rdquo; said Kaitlyn Buss, an ALEC spokeswoman.

Several corporate board members have remained steadfast in their support for the organization.

These companies argue that their participation is limited to issues that directly affect their business. They note that the organization is split into nine task forces made up of state legislators and private sector representatives that serve as a clearinghouse for the legislative proposals.

Pharmaceutical Research and Manufacturers of America, the powerful Washington lobby for prescription drug manufacturers, told Roll Call it would continue to support the organization.

&ldquo;PhRMA has a long history of partnering with and supporting diverse stakeholders and organizations who share our goals of helping patients access the medicines and care they need and fostering medical innovation,&rdquo; Matthew Bennett, a senior vice president of the trade group, said in a statement to Roll Call. &ldquo;As such, our involvement with ALEC concentrates on public health issues that directly relate to these goals.&rdquo;

Dennis Bartlett, the executive director of the American Bail Coalition, another ALEC board member, said he has received upward of 3,000 e-mails prompted by the Color of Change campaign but has no plans to cut ties with ALEC because of the access it gives him to state legislators.